This invention concerns the provision of covers or shields for terminals of battery packs, as used in cordless power tools and the like, for reducing the possibility of unintentional contact, particularly electrically conductive contact, between a terminal and other materials or between two terminals, when the pack is not housed in the tool.
The desirability of avoiding unintentional discharge of any charge present in the cells of the battery pack when handling or disposing of the pack is well understood.
It is also known to create "throw away" power packs or cartridges in which the battery pack cells are enclosed in a housing which includes an end cap or caps of varying degrees of elaboration so that the terminals of the power pack (typically at one end or at opposite ends of the pack) are, at least to some degree, protected. But many such cartridges are expensive to manufacture and use because of their complex structure. Further, and typically, they are not space efficient in that their outside dimensions or overall size may be substantially greater than that required for the cells of the battery pack alone. Also, the cartridge housing may add undesirable weight to the tool or appliance. See for example U.S. Pat. Nos. 4,091,187 Kaye and 3,956,019 Mabuchi.
It is also known to encase the cells of a battery pack in a thin plastic material as for example by the shrink wrap process, at least partly so as to minimize the bulk of the battery pack. See for example U.S. Pat. Nos. 1,277,147 Armande, and 4,166,532 Tsuchida and German patent 2,735,293 Schroder But these disclosures do not suggest provision for maintaining a cover or shielding for the terminals of the pack once it has been prepared for service and/or is about to be discarded.
It is also known to provide simple inexpensive terminal covers, perhaps of cardboard, to shield the terminals of a battery pack when it is shipped or in storage before use. See for example U.S. Pat. Nos. 1,176,467 Koretzky and 1,779,767 Gillingham. But these covers are removed and discarded when the battery pack is prepared for service and hence are not available and in position when it is being handled or when it is discarded.
An incomplete or partial solution to the problem of terminal shielding or covering is offered in the disclosure of British Patent 2,021,849 Ciliberti. The cylindrical side walls of the female terminal of a conventional single 9 volt cell are insulated by a plastic cover using the shrink wrap process.